Precision inertial navigation systems typically require concentric sets of ball bearing supported gimbals which allow instruments to freely rotate in flight maneuvers and allow them to be manipulated for calibration. The embodiments of the previously referenced application Ser. No. 11/004,184, which is herein incorporated by reference, eliminate the need for gimbals and ball bearings by supporting the inertial sensor assembly with a spherically shaped gas bearing. During the flight of a craft, the angular position of the inertial sensor assembly (sometimes also referred to as the attitude, or roll, pitch and yaw of the inertial sensor assembly) relative to the frame of the craft is monitored at all times. The gas bearing allows rotation of the inertial sensor assembly in all axes with no wear due to contact between rotating surfaces.
An inertial sensor assembly typically contains internally embedded instrumentation, such as accelerometers and gyroscopes that communicate data with other craft systems. In inertial navigation systems comprising ball bearing supported gimbals, data from instrumentation supported by the gimbals is typically communicated to other systems through moving contact devices, such as slip rings or twist caps, which provide a constant electrical channel for data without restricting the movement of the inertial sensor assembly. However, slip rings and twist caps, like ball bearing supported gimbals, are moving physical structures subject to wear and therefore represent a potential failure point for an inertial navigation system, or other system. Data signals communicated through slip rings also suffers from noise interference and low bandwidth. Further, communications through slip rings is not possible in applications, such as embodiments of the previously referenced application Ser. No. 11/004,184, where the gimbals are absent and no physical contact is desirable with the inertial sensor assembly.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the specification, there is a need in the art for a contact free instrumentation data channel for communication with deeply embedded systems.